Such gas generator serves to generate compressed gas, by means of which for instance a gas bag of the vehicle occupant restraint system is filled in a case of restraint. For this purpose, the gas generator can include a chamber with stored cold gas, which is released upon activation of the gas generator. Alternatively or in addition (the latter in the case of so-called hybrid gas generators), the gas generator includes a combustion chamber with a pyrotechnical propellant, upon deflagration of which compressed gas is generated. The gas released upon activation of the gas generator emerges from the gas generator through one (or more) outflow opening(s), the outflow opening usually being closed by a sealing material or membrane prior to activation. Once the outflow opening is opened, it has a constant cross-section. However, the outflow cross-section influences the combustion chamber pressure and hence in turn the deflagration behavior of the propellant, in particular in terms of generator performance, gas yield and generation of noxious gases. For this reason, it is desirable that the pressure existing in the combustion chamber does not fall below a certain level.
Therefore, it is the object of the invention to create a gas generator, in which an outflow cross-section is controllable in dependence on the internal pressure.